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Bhopal disaster (1984)

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Jessie Phallon
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« Reply #15 on: June 19, 2009, 01:23:37 pm »

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« Reply #16 on: June 19, 2009, 01:24:05 pm »

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« Reply #17 on: June 19, 2009, 01:24:23 pm »

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« Reply #18 on: June 19, 2009, 01:24:43 pm »

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« Reply #19 on: June 19, 2009, 01:25:03 pm »

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« Reply #20 on: June 19, 2009, 01:25:29 pm »

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« Reply #21 on: June 19, 2009, 01:25:45 pm »

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« Reply #22 on: June 19, 2009, 01:28:39 pm »

Equipment and safety regulations

•   It emerged in 1998, during civil action suits in India, that, unlike Union Carbide plants in the USA, its Indian subsidiary plants were not prepared for problems. No action plans had been established to cope with incidents of this magnitude. This included not informing local authorities of the quantities or dangers of chemicals used and manufactured at Bhopal.[1][2][3][17]
•   The MIC tank alarms had not worked for 4 years.[1][2][3][21]
•   There was only one manual back-up system, not the four-stage system used in the USA.[1][2][3][21]
•   The flare tower and the vent gas scrubber had been out of service for 5 months before the disaster. The gas scrubber therefore did not treat escaping gases with sodium hydroxide (caustic soda), which might have brought the concentration down to a safe level.[21] Even if the scrubber had been working, according to Weir, investigations in the aftermath of the disaster discovered that the maximum pressure it could handle was only one-quarter of that which was present in the accident. Furthermore, the flare tower itself was improperly designed and could only hold one-quarter of the volume of gas that was leaked in 1984.[1][2][3][22]
•   To reduce energy costs, the refrigeration system, designed to inhibit the volatilization of MIC, had been left idle — the MIC was kept at 20 degrees Celsius, not the 4.5 degrees advised by the manual, and some of the coolant was being used elsewhere.[1][2][3][21]
•   The steam boiler, intended to clean the pipes, was out of action for unknown reasons.[1][2][3][21]
•   Slip-blind plates that would have prevented water from pipes being cleaned from leaking into the MIC tanks through faulty valves were not installed. Their installation had been omitted from the cleaning checklist.[1][2][3]
•   Water sprays designed to “knock down” gas leaks were poorly designed — set to 13 metres and below, they could not spray high enough to reduce the concentration of escaping gas.[1][2][3][21]
•   The MIC tank had been malfunctioning for roughly a week. Other tanks had been used for that week, rather than repairing the broken one, which was left to “stew”. The build-up in temperature and pressure is believed to have affected the magnitude of the gas release.[1][2][3][21]
•   Carbon steel valves were used at the factory, even though they corrode when exposed to acid.[17] On the night of the disaster, a leaking carbon steel valve was found, allowing water to enter the MIC tanks. The pipe was not repaired because it was believed it would take too much time and be too expensive.[1][2][3][21]
•   UCC admitted in their own investigation report that most of the safety systems were not functioning on the night of the December 3, 1984.[12]
•   Themistocles D'Silva contends that the design of the MIC plant, following government guidelines, was "Indianized" by UCIL engineers to maximize the use of indigenous materials and products. It also dispensed with the use of sophisticated instrumentation as not appropriate for the Indian plant. Because of the unavailability of electronic parts in India, the Indian engineers preferred pneumatic instrumentation.[23]

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« Reply #23 on: June 19, 2009, 01:29:03 pm »

•   It emerged in 1998, during civil action suits in India, that, unlike Union Carbide plants in the USA, its Indian subsidiary plants were not prepared for problems. No action plans had been established to cope with incidents of this magnitude. This included not informing local authorities of the quantities or dangers of chemicals used and manufactured at Bhopal.[1][2][3][17]
•   The MIC tank alarms had not worked for 4 years.[1][2][3][21]
•   There was only one manual back-up system, not the four-stage system used in the USA.[1][2][3][21]
•   The flare tower and the vent gas scrubber had been out of service for 5 months before the disaster. The gas scrubber therefore did not treat escaping gases with sodium hydroxide (caustic soda), which might have brought the concentration down to a safe level.[21] Even if the scrubber had been working, according to Weir, investigations in the aftermath of the disaster discovered that the maximum pressure it could handle was only one-quarter of that which was present in the accident. Furthermore, the flare tower itself was improperly designed and could only hold one-quarter of the volume of gas that was leaked in 1984.[1][2][3][22]
•   To reduce energy costs, the refrigeration system, designed to inhibit the volatilization of MIC, had been left idle — the MIC was kept at 20 degrees Celsius, not the 4.5 degrees advised by the manual, and some of the coolant was being used elsewhere.[1][2][3][21]
•   The steam boiler, intended to clean the pipes, was out of action for unknown reasons.[1][2][3][21]
•   Slip-blind plates that would have prevented water from pipes being cleaned from leaking into the MIC tanks through faulty valves were not installed. Their installation had been omitted from the cleaning checklist.[1][2][3]
•   Water sprays designed to “knock down” gas leaks were poorly designed — set to 13 metres and below, they could not spray high enough to reduce the concentration of escaping gas.[1][2][3][21]
•   The MIC tank had been malfunctioning for roughly a week. Other tanks had been used for that week, rather than repairing the broken one, which was left to “stew”. The build-up in temperature and pressure is believed to have affected the magnitude of the gas release.[1][2][3][21]
•   Carbon steel valves were used at the factory, even though they corrode when exposed to acid.[17] On the night of the disaster, a leaking carbon steel valve was found, allowing water to enter the MIC tanks. The pipe was not repaired because it was believed it would take too much time and be too expensive.[1][2][3][21]
•   UCC admitted in their own investigation report that most of the safety systems were not functioning on the night of the December 3, 1984.[12]
•   Themistocles D'Silva contends that the design of the MIC plant, following government guidelines, was "Indianized" by UCIL engineers to maximize the use of indigenous materials and products. It also dispensed with the use of sophisticated instrumentation as not appropriate for the Indian plant. Because of the unavailability of electronic parts in India, the Indian engineers preferred pneumatic instrumentation.[23]
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« Reply #24 on: June 19, 2009, 01:29:36 pm »

Previous warnings and accidents

A series of prior warnings and MIC-related accidents had occurred:
•   In 1976, the two trade unions reacted because of pollution within the plant.[1][2][16]
•   In 1981, a worker was splashed with phosgene. In panic he ripped off his mask, thus inhaling a large amount of phosgene gas; he died 72 hours later.[1][2][16]
•   In January 1982, there was a phosgene leak, when 24 workers were exposed and had to be admitted to hospital. None of the workers had been ordered to wear protective masks.
•   In February 1982, an MIC leak affected 18 workers.[1][2][16]
•   In August 1982, a chemical engineer came into contact with liquid MIC, resulting in burns over 30 percent of his body.[1][2][16]
•   In October 1982, there was a leak of MIC, methylcarbaryl chloride, chloroform and hydrochloric acid. In attempting to stop the leak, the MIC supervisor suffered intensive chemical burns and two other workers were severely exposed to the gases.[1][2][16]
•   During 1983 and 1984, leaks of the following substances regularly took place in the MIC plant: MIC, chlorine, monomethylamine, phosgene, and carbon tetrachloride, sometimes in combination.[1][2][16]
•   Reports issued months before the incident by scientists within the Union Carbide corporation warned of the possibility of an accident almost identical to that which occurred in Bhopal. The reports were ignored and never reached senior staff.[2][17]
•   Union Carbide was warned by American experts who visited the plant after 1981 of the potential of a "runaway reaction" in the MIC storage tank; local Indian authorities warned the company of problems on several occasions from 1979 onwards. Again, these warnings were not heeded.[2][17]

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« Reply #25 on: June 19, 2009, 01:31:08 pm »

The leakage

•   In November 1984, most of the safety systems were not functioning. Many valves and lines were in poor condition. Tank 610 contained 42 tonnes MIC, much more than allowed according to safety rules.[1][2]
•   During the nights of 2–3 December, a large amount of water entered tank 610. A runaway reaction started, which was accelerated by contaminants, high temperatures and other factors. The reaction generated a major increase in the temperature inside the tank to over 200°C (400°F). This forced the emergency venting of pressure from the MIC holding tank, releasing a large volume of toxic gases. The reaction was sped up by the presence of iron from corroding non-stainless steel pipelines.[1][2]
•   It is known that workers cleaned pipelines with water. They were not told by the supervisor to add a slip-blind water isolation plate. Because of this, and of the bad maintenance, the workers consider it possible for water to have accidentally entered the MIC tank.[1][2][3]
•   UCC maintains that a "disgruntled worker" deliberately connected a hose to a pressure gauge. [1][2][10]
•   UCC's investigation team found no evidence of the suggested connection.[11]
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« Reply #26 on: June 19, 2009, 01:32:05 pm »

The leakage Timeline, summary

At the plant[1][2]
•   21.00 Water cleaning of pipes starts.
•   22.00 Water enters tank 610, reaction starts.
•   22.30 Gases are emitted from the vent gas scrubber tower.
•   00.30 The large siren sounds and is turned off.
•   00.50 The siren is heard within the plant area. The workers escape.
Outside[1][2]

•   22.30 First sensations due to the gases are felt — suffocation, cough, burning eyes and vomiting.
•   1.00 Police are alerted. Residents of the area evacuate. Union Carbide director denies any leak.
•   2.00 The first people reached Hamidia hospital. Symptoms include visual impairment and blindness, respiratory difficulties, frothing at the mouth, and vomiting.
•   2.10 The alarm is heard outside the plant.
•   4.00 The gases are brought under control.
•   6.00 A police loudspeaker broadcasts: "Everything is normal".
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« Reply #27 on: June 19, 2009, 01:32:54 pm »

Health effects
Short term health effects

•   Apart from MIC, the gas cloud may have contained phosgene, hydrogen cyanide, carbon monoxide, hydrogen chloride, oxides of nitrogen, monomethyl amine (MMA) and carbon dioxide, either produced in the storage tank or in the atmosphere.[1][2]
•   The gas cloud composed mainly of materials denser than the surrounding air, stayed close to the ground and spread outwards through the surrounding community. The initial effects of exposure were coughing, vomiting, severe eye irritation and a feeling of suffocation. People awakened by these symptoms fled away from the plant. Those who ran inhaled more than those who had a vehicle to ride. Owing to their height, children and other people of shorter stature inhaled relatively higher concentrations. Many people were trampled trying to escape.[1][2]
•   Thousands of people had succumbed by the morning hours. There were mass funerals and mass cremations as well as disposal of bodies in the Narmada river. 170,000 people were treated at hospitals and temporary dispensaries. 2,000 buffalo, goats, and other animals were collected and buried. Within a few days, leaves on trees yellowed and fell off. Supplies, including food, became scarce owing to suppliers' safety fears. Fishing was prohibited as well, which caused further supply shortages.[1][2]
•   A total of 36 wards were marked by the authorities as being "gas affected", affecting a population of 520,000. Of these, 200,000 were below 15 years of age, and 3,000 were pregnant women. In 1991, 3,928 deaths had been certified. Independent organizations recorded 8,000 dead in the first days. Other estimations vary between 10,000 and 30,000. Another 100,000 to 200,000 people are estimated to have permanent injuries of different degrees.[1][2]
•   The acute symptoms were burning in the respiratory tract and eyes, blepharospasm, breathlessness, stomach pains and vomiting. The causes of deaths were choking, reflexogenic circulatory collapse and pulmonary oedema. Findings during autopsies revealed changes not only in the lungs but also cerebral oedema, tubular necrosis of the kidneys, fatty generation of the liver and necrotising enteritis.[24] The stillbirth rate increased by up to 300% and neonatal mortality rate by 200 %.[1][2]
•   

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« Reply #28 on: June 19, 2009, 01:33:47 pm »

Hydrogen cyanide or not?

•   Whether hydrogen cyanide was present in the gas mixture is still a controversy.[24][25]
•   Exposed at higher temperatures, MIC breaks down to hydrogen cyanide (HCN). According to Kulling & Lorin, at +200°C, 3 % of the gas is HCN.[26] However, according to another scientific publication,[27] MIC when heated in the gas-phase starts breaks down to hydrogen cyanide (HCN) and other products above 400°C. Concentrations of 300 ppm can lead to immediate collapse.
•   Laboratory replication studies by CSIR and UCC scientists failed to detect any HCN. </ref> Chemically, HCN is known to be very reactive with MIC. [28]
•   The non-toxic antidote sodium thiosulfate (NaTs) in intravenous injections increases the rate of conversion from cyanide to non-toxic thiocyanate. Treatment was suggested early, but because of confusion within the medical establishments, it was not used on larger scale until June 1985.[1][2]
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« Reply #29 on: June 19, 2009, 01:34:30 pm »

Long term health effects

•   It is estimated that 20,000 have died since the accident from gas-related diseases. Another 100,000 to 200,000 people are estimated to have permanent injuries.[1][2]
•   The quality of the epidemiological and clinical research varies. Reported and studied symptoms are eye problems, respiratory difficulties, immune and neurological disorders, cardiac failure secondary to lung injury, female reproductive difficulties, and birth defects among children born to affected women. Other symptoms and diseases are often ascribed to the gas exposure, but there is no good research supporting this.[1][2]
•   The best, most credible research comes from a clinic established by a group of survivors and activists known as Sambhavna. Sambhavna is the only clinic that will treat anybody affected by the gas, or the subsequent water poisoning, and treats the condition with a combination of Western and traditional Indian medicines, and has performed extensive research, see: http://bhopal.org/index.php?id=20
•   Union Carbide as well as the Indian Government long denied permanent injuries by MIC and the other gases. In January, 1994, the International Medical Commission on Bhopal (IMCB) visited Bhopal to investigate the health status among the survivors as well as the healthcare system and the socio-economic rehabilitation.
•   The reports from Indian Council of Medical Research[15] were not completely released until around 2003.
•   For a review of the research on the health effects of the Bhopal disaster, see Dhara & Dhara (2002).[29]
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